The present invention relates to a supply unit for fuel injection apparatus of an internal combustion engine, comprising a manifold defining a duct for supplying the fuel to the injectors of the engine and a pressure regulator which can maintain the pressure of the fuel substantially constant within the manifold itself.
In fuel supply apparatus of this type it is very important to maintain the pressure of the fuel within the manifold substantially constant: for this purpose the manifold is provided with a connector to which is connected a pressure regulator of conventional type, substantially comprising a chamber in communication with the manifold and one wall of which is constituted by a deformable diaphragm, and a valve operable to put the manifold into communication with a discharge hole the opening of which is controlled by the said deformable diaphragm.
Known units comprising a manifold and a pressure regulator briefly described above have several disadvantages.
First of all they are structurally rather complex because of the numerous parts of which they are constituted and the connection members which are necessary to fix the pressure regulator to the manifold. Moreover, the pressure regulation effected by these units takes place with a certain delay because of the large volume of the ducts which connect the said chamber of the pressure regulator to the manifold. Finally, the unit thus formed has rather large dimensions which make its application in some types of motor vehicle problematical.